Members of the Luteoviridae, such as Barley yellow dwarf virus (BYDV), Potato leaf roll virus (PLRV) and Beet western yellows virus (BWYV) are crop pathogens of global economic importance (Sylvester, E. S. 1989. A. K. Minks and P. Harrewiojn, Amsterdam, Elsevier. C:65-88; Blackman, R. L. 2000. An identification and information guide. New York, John Wiley and Sons). During aphid feeding, the virions of such plant viruses that are transmitted in a persistent or circulative manner, pass with the sap through the maxillary food canal of the aphid stylet into the gut. From the gut (midgut or hindgut) the virions penetrate the gut epithelium by endocytosis (Gildow, F. E. et al. 1993. Phytopathology 83:1293-1302; Gray, S. M. 1996. Trends Microbiol. 4(7):259-264) (FIG. 1). The virus-containing vesicle fuses with the plasmalemma, thereby releasing the virus, which readily passes through the basement membrane into the hemocoel. The virus is then transported to the accessory salivary gland (ASG). Upon aphid feeding, the luteovirus is injected into the plant with saliva via the salivary canal in the maxillary stylets (FIG. 1).
The transmission of plant viruses involves specific molecular interactions between the virus and its vector: For aphid transmission of luteoviruses, the virus must bind to a receptor in the gut for uptake into the hemocoel, where the virus circulates. A second receptor is involved in movement of virus from the hemocoel into the accessory salivary gland (ASG), from which the virus is delivered with the aphid saliva into the phloem of the plant. Despite several attempts, no aphid receptor involved in plant virus—aphid interaction has been identified.
There is a long felt need in the art for environmentally friendly and economical methods for reducing damage to both crop and ornamental plants from virus infection. The present invention meets this need.